In many construction situations there is a need to drill a hole in a material, e.g. concrete from a floor or wall. A core drill bit, also referred to as a circular drill bit or hole-saw, is commonly used for such purpose. The drilling process results in a concrete core being separated from the material, which can fall from the drill bit and cause damage or injury.
JP 11320548 (Suetsugi) discloses a concrete drop prevention device or concrete safety catcher for a core drill. The concrete safety catcher is adapted to hang the concrete by a connecting mechanism and a concrete anchor after drilling of the concrete to prevent the concrete from falling. The anchor is arranged in the core bit to act as the concrete safety catcher when the core drill drills a cylindrical hole through the concrete. The connecting mechanism is arranged in the core bit and connects an upper wall and the concrete anchor of the core bit.
JP 7171821 (Onishi, et al.) discloses a take-up device independent of rotation of a drill to eliminate the twist and break of a string belt by a method wherein a fixed base part is provided in a closed-end cylindrical drill. The take-up device is disposed downward of the fixed base part, which is connected to the take-up device by a rotating shaft, and the take-up device is rotated on ball bearings.
U.S. Pat. No. 7,484,578 (Duncan) discloses an apparatus for drilling holes in a substrate wherein a mandrel is anchored to the substrate. A hollow drill bit rotates about the mandrel via a drive motor and is a guided along a length of the mandrel.
U.S. Pat. No. 6,881,016 and U.S. 2004/191,014 (May) disclose a core retainer having a base plate releasably attached to a concrete floor from which a concrete core is to be removed. A brake assembly atop the plate includes a plurality of brake pads for contact with the interior of the core drill bit. The retainer is configured to fit within the core drill bit and either rotate with the core drill bit or be stationary relative thereto. Upon drilling, the plate and separated core fall toward the floor below. This movement is translated to the brake assembly by the linkage such that the brake pads engage the inner circular wall of the core drill bit at a sufficient pressure allowing for the separated core to be retained within the core drill bit.